This invention relates to a process for producing an aqueous emulsion of unsaturated resin having reactive unsaturated groups.
In recent years, the method for curing coating films by means of radiant rays such as electron beams and ultraviolet rays has been widely noted and the development of unsaturated resins suitable for such method has been undertaken. When the conventional unsaturated resins are used for vehicles of varnishes or enamels, they are usually diluted with reactive unsaturated monomers or common organic solvents. The coating composition prepared therefrom are than applied to the surfaces of substrates and the radiant energy such as electron beams or ultraviolet rays is applied to the coated surfaces so as to form a cross-linked coating film.
Advantages of radiation curing resin exist in the saving of resources and the prevention of environmental pollution, however, conventional coating compositions containing the radiation curing resin is far from these attributes, that is, the monomers and solvents contained in the coating composition are vaporized during the coating and curing operation. Accordingly, the unsaturated resins which do not give off the vapor of organic solvents, in other words, liquid high-boiling unsaturated oligomers or water-soluble or water-dispersible unsaturated resins are eagerly desired.